The typical bicycle has a fork which is open or notched at the bottom or free end of both sides. The front wheel, hub, bearings and axle are first assembled as one. The axle is threaded at each end. The axle assembly carrying the front wheel is then slidably received in the U-shaped notched open ends of the fork and nuts are engaged on the threads to hold the wheel on the fork.
This type of fork, sometimes referred to as a pair of clevises each with a pair of arms, is adapted to be received on bike racks or carriers usually positioned on the roof of an automobile or in the bed of a truck. The carrier is adapted to hold the bike in an upright vertical position. The wheel of the bike is first removed by loosening the nuts and the fork is slipped over the carrier which has a transverse rod or skewer assembly having threaded ends. The fork is positioned on the rod in much the same way as the front wheel axle fits in the open ends of the fork. The nuts are made up on the threaded ends of the rod securing the bike.
All of the foregoing is prior art. See, for example, Stephens, U.S. Pat. No. 5,265,897.
This arrangement is not suitable for many down hill trail bikes which are used on extremely rough terrain. The pounding and distortion produced under downhill trail biking conditions can result in the loosening of the front wheel, with dire consequences. Consequently, in such bikes, the fork is not open at its free ends, that is, there is no U-shaped notch or spaced apart arms in either clevis. Instead, the fork has closed free ends with round through holes formed or drilled therein for receiving the front axle. The front axle is slid through the holes and front wheel hub after the wheel has been positioned between each side of the fork.
This presents a problem since such downhill or trail bicycles are incompatible with the standard bike rack or carrier in which the fork end is received over a rod or skewer assembly.
The present invention pertains to an extension for the through axle or mountain bike forks so that it can be carried on the same bike rack or carrier as is used for bikes having notched open end forks.